Conventionally, a so-called automatic clutch is known which combines an actuator with a friction clutch such that the clutch is automatically disconnected and connected.
However, a vehicle only equipped with the automatic clutch cannot run when the system is broken. Further, the following fail-safe measure is only available: the clutch is automatically disconnected, connected or maintained in the present condition when the system becomes out of order.
In consideration of the above, a so-called semi-automatic clutch is proposed to overcome the above shortcomings. By using the semi-automatic clutch, manual disconnection and connection of a clutch with a clutch pedal is also made available in addition to the automatic disconnection and connection (Japanese Utility Model Application, Laid-Open Publication No. 6-8825).
Incidentally, the semi-automatic clutch has a problem of interference between the automatic disconnection/connection and manual disconnection/connection when the automatic clutch operation is switched to the manual operation or vice versa. For example, if the one (automatic or manual) clutch disconnection/connection mode is switched to the other mode while the clutch disconnection is proceeding in the above-mentioned one mode, a clutch may immediately be brought into a connecting condition thereby causing a connection shock and unexpectedly rapid acceleration of a vehicle.
An object of the present invention is to provide a clutch disconnection/connection apparatus which can prevent occurrence of a connection shock and accidental acceleration of a vehicle when the switching between the automatic disconnection/connection mode and the manual disconnection/connection mode takes place.